Modern vehicles include a vast array of sensors, such as air bag sensors, tire pressure sensors, engine sensors, seat belt sensors, and many others. The sensors provide data about the vehicle's operation (e.g., wheel speed, deceleration, etc.) to an automotive control unit (ACU). Based on the data received from the sensors, the ACU can determine if an action should be taken (e.g., when air bags within a vehicle should be deployed).
FIG. 1 shows a vehicular sensing system 100 including a sensor interface module 102. The sensor interface module 102 has a control unit interface 104 coupled to a control unit 106 and a sensor interface 108 connected to one or more sensors 110 (e.g., 110a, . . . , 110n).
To transmit information to the sensors 110, the sensor interface module 102 includes a modulation unit 112, which modulates a supply voltage (e.g., a change in the DC supply voltage) to transmit information to at least one of the sensors 112. When data is not transmitted, the modulation unit 112 often provides an un-modulated (e.g., DC) supply voltage to the sensors 110. To receive information from the sensors 110, the sensor interface module 102 includes a demodulation unit 114, which demodulates a modulated sensor current signal to receive information from at least one of the sensors 110.